X-ray imaging system

Abstract

An X-ray detector 1 includes: an X-ray line sensor 3 which is arranged in a straight line in the horizontal direction such that a plurality of X-ray detecting elements 35 face an X-ray source 5; and a collimator portion 2, which comprises a pair of plate-shaped portions arranged facing each other in the vertical direction, is disposed on the X-ray source 5 side of an end portion of the X-ray line sensor 3 so as to sandwich the X-ray line sensor 3 when viewed from the X-ray source 5 side, and which introduces an X-ray 7 into the X-ray detecting elements 35. A movement control mechanism 11 has a first drive portion 11a and a second drive portion 11b that move the X-ray detector 1 such that the direction in which the X-ray 7 is introduced into the collimator portion 2 is directed toward the X-ray source 5. An X-ray introduction width d2 of the collimator portion 2 is greater than a thickness d1 of the X-ray detecting elements 35, and a blocking portion 2S for blocking the incidence of the X-ray 7 is provided on the outside, in the vertical direction, of the X-ray line sensor 3.

Description

X-ray imaging system

[0001] The present invention relates to an X-ray imaging system.

[0002] In recent years, the deterioration of structures such as bridges has become a problem, and maintenance is an urgent need. X-ray transmission imaging inspection is an example of a method for non-destructively inspecting the interior of a structure for such maintenance. In this X-ray transmission imaging inspection, for example, an X-ray detector using an X-ray line sensor is used. X-ray detectors using X-ray line sensors are used in non-destructive inspection for security and industrial purposes.

[0003] For example, Patent Document 1 describes an X-ray imaging system that includes an X-ray source that irradiates X-rays, a detector that detects X-rays that have passed through a subject, a semiconductor detector array that moves inside the detector, a semiconductor detector array drive unit that moves the semiconductor detector array up and down, and a signal processing circuit that processes measurement signals measured by the detector to create an image. This X-ray imaging system uses a semiconductor detector that is highly sensitive to high-energy X-rays.

[0004] Japanese Patent Application Publication No. 2015-225053

[0005] When an X-ray detector using an X-ray line sensor scans, the X-ray line sensor is moved up and down and the orientation of the X-ray detector is controlled to be centered on the X-ray source. A collimator is installed on the front surface (X-ray source side) of the X-ray detector, and the vertical width of the collimator is set to be approximately the same as the width (thickness) of the X-ray detection elements that make up the X-ray line sensor. Therefore, when the orientation of the X-ray detector is controlled to be centered on the X-ray source, for example, if the angle of the X-ray detector is misaligned, the X-rays may be blocked by the collimator, causing a shadow on the X-ray transmission image, which may result in a failure to obtain a normal X-ray transmission image.

[0006] For example, under actual inspection environmental conditions, even a deviation of just 1 degree from the angle of the X-ray detector will result in most of the X-rays being blocked by the collimator, resulting in a significant drop in the measurement signal from the X-ray detector. It is therefore difficult to control the angle of the X-ray detector without variation.

[0007] Furthermore, there are cases where unnecessary X-rays such as scattered rays are incident on the X-ray detector, and in such cases, noise information due to the scattered rays is included in the generated X-ray transmission image, which may make it impossible to obtain a good X-ray transmission image. Therefore, there is a need for the development of an X-ray imaging system that can prevent shadows from appearing in the X-ray transmission image.

[0008] The present invention provides an X-ray imaging system capable of suppressing the occurrence of shadows in an X-ray transmission image.

[0009] The present invention provides an X-ray imaging system comprising: an X-ray source that irradiates X-rays; an X-ray detector that is arranged to face the X-ray source across an object and detects the X-rays that have passed through the object; and a movement control mechanism that moves the X-ray detector in a predetermined direction, wherein the X-ray detector comprises: an X-ray line sensor that is arranged linearly along a direction intersecting the predetermined direction so that a plurality of X-ray detection elements face the X-ray source; and a collimator unit that is a pair of plate-like parts that are arranged opposite to the predetermined direction, sandwiching the X-ray line sensor when viewed from the X-ray source side and that is arranged closer to the X-ray source than an end of the X-ray line sensor, and that introduces the X-rays into the X-ray detection elements, and the movement control mechanism has a mechanism that moves the X-ray detector so that the introduction direction of the X-rays in the collimator unit faces the X-ray source, and the X-ray introduction width of the collimator unit, which is the distance between the pair of plate-like parts, is greater than the thickness of the X-ray detection elements, In the X-ray imaging system, a shielding portion that blocks incidence of the X-rays is provided on the outer side of the X-ray line sensor in the predetermined direction.

[0010] According to the present invention, it is possible to prevent shadows from appearing in an X-ray transmission image while allowing for slight angular deviation of the X-ray detector.

[0011] 4 is a perspective view showing the configuration of an X-ray imaging system 100 in a first embodiment. FIG. 5 is a side view of the X-ray imaging system 100 in the X-Z plane. FIG. 6 is a perspective view showing the configuration inside a housing 4. FIG. 7 is a diagram schematically showing the configuration of an X-ray detector 1 and the configuration of a control unit 20 and the like connected to the X-ray detector 1. FIG. 8 is a cross-sectional view taken along the line A-A in FIG. 4. FIG. 9 is a diagram showing the relationship between the X-ray introduction width d2 of the collimator unit 2 and the thickness d1 of the X-ray detection element 35. FIG. 10 is a diagram showing the relationship between the X-ray introduction width of the collimator unit 2 and the thickness of the X-ray detection element 35 in a conventional X-ray detector. FIG. 11 is a diagram showing the relationship between the collimator unit 2 and the X-ray line sensor 3. FIG. 12 is a diagram for explaining an example of the X-ray introduction width d2 of the collimator unit 2. FIG. 13 is a diagram for explaining another example of the X-ray introduction width d2 of the collimator unit 2. FIG. 14 is a diagram showing an example of a comparison of X-ray transmission images obtained by the X-ray detector 1 in the first embodiment and the conventional X-ray detector. FIG. 15 is a schematic diagram showing the configuration of an X-ray imaging system 100 in a second embodiment. FIG. 16 is a diagram for explaining a fourth embodiment, showing an example of an X-ray output waveform when the X-ray source 5 is a pulsed X-ray source. FIG. 10 is a schematic diagram showing the configuration of an X-ray imaging system 100 in a fifth embodiment. FIG. 11 is a diagram for explaining a sixth embodiment, showing an example in which there are multiple X-ray detection element rows and the detection areas are different. FIG. 12 is a diagram for explaining a seventh embodiment, showing an example in which there are multiple X-ray detection element rows and the X-ray detection element rows are shifted in the horizontal direction. FIG. 13 is a diagram showing another example of the positional relationship between a shielding section 2S and a collimator section 2. FIG. 14 is a diagram showing another example of the positional relationship between a shielding section 2S and a collimator section 2. FIG. 15 is a diagram showing another example of the positional relationship between a shielding section 2S and a collimator section 2.

[0012] Hereinafter, embodiments of the X-ray imaging system of the present invention will be described with reference to the accompanying drawings. The drawings should be viewed in the direction indicated by the reference numerals.

[0013] First Embodiment First, an X-ray imaging system according to a first embodiment will be described with reference to FIGS.

[0014] 1 and 2, the X-ray imaging system 100 includes an X-ray source 5 that irradiates an object 6 with X-rays, and an X-ray detector 1 that detects X-rays 7. The X-ray source 5 and the X-ray detector 1 are arranged to face each other with the object 6 therebetween.

[0015] The X-ray source 5 includes an X-ray tube (not shown), and generates X-rays 7 when a high voltage is applied thereto, and irradiates the generated X-rays 7 toward the subject 6, for example, in the form of a cone beam. The X-rays 7 irradiated onto the subject 6 are attenuated as they pass through the subject 6, and then enter the X-ray detector 1. The energy range of the X-rays 7 generated from the X-ray source 5 may be within a predetermined range, and is expected to be high energy, for example, from several tens of keV to 100 keV or more. The subject 6 may be, for example, a structure used in public infrastructure, such as a bridge, a tunnel, a road, or concrete.

[0016] The X-ray detector 1 includes a collimator unit 2 and an X-ray line sensor 3. The X-ray line sensor 3 has X-ray detection elements 35 that detect X-rays (shown in FIG. 4 ). The X-ray detection elements 35 are linearly arranged along a direction intersecting a predetermined direction so as to face the X-ray source 5. For example, in the example shown in FIG. 4 , the X-ray detection elements 35 are linearly arranged along a horizontal direction (±Y direction) that intersects with the up-down direction (±Z direction). Note that the "intersecting direction" may be assumed to be a direction perpendicular to the up-down direction, but it does not necessarily have to be perpendicular to the up-down direction as long as the X-ray detection elements 35 are arranged horizontally. The X-ray line sensor 3 detects X-rays 7 incident via the collimator unit 2. The collimator unit 2 is a pair of plate-like members arranged opposite each other in the up-down direction (±Z direction). The collimator units 2 are arranged on either side of the X-ray line sensor 3 when viewed from the X-ray source 5, and are positioned closer to the X-ray source 5 than the end of the X-ray line sensor 3. The collimator unit 2 introduces X-rays 7 into the X-ray line sensor 3 while preventing unnecessary X-rays (e.g., scattered rays) from entering the X-ray line sensor 3. The specific configuration of the X-ray line sensor 3 and the more detailed relationship between the X-ray line sensor 3 and the collimator unit 2 will be described later.

[0017] The X-ray detector 1 is disposed in an X-ray detection box 1a that houses the X-ray detector 1. Furthermore, the X-ray detector 1 moves as the X-ray detection box 1a moves inside the housing 4. This movement is performed by a movement control mechanism 11 that moves the X-ray detection box 1a including the X-ray detector 1 in the vertical direction.

[0018] FIG. 3 is a perspective view showing the internal configuration of the housing 4. Note that FIG. 3 shows a state in which the outermost peripheral wall surface is removed from the housing 4. The movement control mechanism 11 has a first drive unit 11a and a second drive unit 11b that are movable up and down on guide rails 12 provided on support columns at the four corners of the housing 4. The first drive unit 11a is capable of moving the collimator unit 2 side of the X-ray detector 1 up and down via the X-ray detection box 1a. The second drive unit 11b is capable of moving the X-ray line sensor 3 side of the X-ray detector 1 up and down via the X-ray detection box 1a. In other words, the first drive unit 11a and the second drive unit 11b can independently control the amount of movement.

[0019] The X-ray detector 1 is controlled so that the X-ray detection elements 35 face the direction of the X-ray source 5 as the X-ray detector 1 moves up and down. Specifically, in accordance with the vertical movement of the X-ray detector 1, the X-ray detector 1 is tilted with respect to the horizontal plane so that the X-ray introduction direction in the collimator unit 2 (hereinafter referred to as the X-ray introduction direction) faces the center of the X-ray source 5. In other words, in accordance with the vertical movement of the X-ray detector 1, the X-ray detector 1 is rotated around the horizontal axis. Then, by tilting the X-ray detector 1 with respect to the horizontal plane, the irradiation direction of the irradiated X-rays and the X-ray introduction direction of the collimator unit 2 are made to coincide. As a result, when the X-ray detector 1 is moved within the housing 4, the X-ray detector 1 is positioned so that the X-ray detector 1 faces the center of the X-ray source 5 regardless of the height at which the X-ray detector 1 is positioned, and deviation of the orientation of the X-ray detection elements 35 with respect to the X-ray source 5 can be suppressed.

[0020] The movement of the X-ray detector 1, i.e., the movement of the X-ray detector 1 by the first drive unit 11a and the second drive unit 11b, is performed by, for example, an actuator (not shown). The amount of movement of the first drive unit 11a and the second drive unit 11b is controlled by instructions from a control unit 20 (shown in FIG. 4) that is composed of a processor or the like. That is, the control unit 20 instructs the actuator on the amount of movement, and the actuator operates the first drive unit 11a and the second drive unit 11b in accordance with the instruction, thereby moving the X-ray detector 1 up and down and controlling its tilt with respect to the horizontal plane.

[0021] Here, a specific configuration of the X-ray line sensor 3 will be described. As shown in FIGS. 4 and 5 , the X-ray line sensor 3 has X-ray detection elements 35, which are continuously arranged in a horizontal line. In other words, the X-ray detection elements 35 are arranged in an array. Separators (not shown) are provided between adjacent X-ray detection elements 35 to prevent crosstalk between the X-ray detection elements 35. In this way, the X-ray line sensor 3 is composed of the X-ray detection elements 35 and the separators. Note that crosstalk is a phenomenon in which X-rays irradiated to the X-ray detector 1 are scattered and the scattered X-rays (i.e., scattered rays) are detected by adjacent X-ray detection elements 35, and this causes degradation of the generated X-ray transmission image.

[0022] The X-ray detection element 35 also has a scintillator 31 that receives the irradiated X-rays 7 and emits scintillation light, and a photodetector 32 that detects the scintillation light. The photodetector 32 is provided on a substrate 33, and the scintillator 31 is disposed above the photodetector 32 (in the Z direction). In order to prevent the scintillation light from leaking to the outside within the region separated by the separator, a reflective film may be formed on the surface other than the photodetector 32 side, and an optical waveguide film may be provided on the surface on the photodetector 32 side to guide the scintillation light to the photodetector 32.

[0023] A signal processing circuit 10 is connected to the other end (X direction) of the substrate 33. The signal processing circuit 10 processes the measurement signal measured by the X-ray detector 1 to generate an image. The signal processing circuit 10 may be integrated with the substrate 33. Wiring connecting the photodetector 32 and the signal processing circuit 10 is formed on the substrate 33. The signal processing circuit 10 amplifies the measurement signal from the photodetector 32, converts the amplified analog signal into a digital signal, and generates an X-ray transmission image based on the converted digital signal. The number of X-ray detection elements 35 arranged in the X-ray line sensor 3 is, for example, 512. In the first embodiment, the number is divided into four, each with 128 elements, and the four signal processing circuits 10 process the divided measurement signals in parallel.

[0024] The X-ray transmission image output from the signal processing circuit 10 is then output to the control unit 20, and the generated X-ray transmission image is output to a display unit 30 such as a monitor.

[0025] According to the X-ray imaging system 100 configured in this manner, the X-ray detector 1 is moved vertically by the movement control mechanism 11 while controlling the X-ray detection elements 35 to face the X-ray source, and the subject 6 is scanned with the X-ray detector 1, and the measurement signals detected by the X-ray detector 1 are converted into an image by the signal processing circuit 10 to output an X-ray transmission image, thereby enabling non-destructive testing of the subject 6.

[0026] Next, the relationship between the X-ray line sensor 3 and the collimator unit 2 will be described. As described above, the movement control mechanism 11 controls the movement of the X-ray detector 1 so that the X-ray detection elements 35 face the X-ray source. Specifically, as shown in FIG. 6 , the movement control mechanism 11 moves the X-ray detector 1 in the vertical direction (±Z direction) and tilts the X-ray detector 1 so that the X-ray line sensor 3 faces the center of the X-ray source 5 according to the angle θ at which the X-rays 7 arrive, thereby aligning the direction in which the X-rays 7 arrive with the X-ray introduction direction of the collimator unit 2. Here, as shown in FIG. 7 , when irradiation of the X-rays 7 causes an angular deviation θ1 between the direction in which the X-rays 7 arrive at the collimator unit 2 and the X-ray introduction direction 2a of the collimator unit 2, in a conventional X-ray detector, the X-rays 7 that would have arrived at the X-ray line sensor 3 if there was no angular deviation θ1 may strike the vicinity of the tip or the inner wall of the collimator unit 2. 7, in the conventional X-ray detector, the X-ray introduction width d2 of the collimator unit 2 is substantially the same as the thickness d1 of the X-ray detection element 35 (this also applies to the conventional X-ray detectors described below). In such a case, an area in the front surface of the collimator unit 2 (the surface of the X-ray source 5) where the X-rays 7 cannot be detected occurs, causing shadows and the like in the generated image, making it impossible to obtain the desired resolution or detection sensitivity.

[0027] 6, the X-ray detector 1 of the first embodiment is configured so that the X-ray introduction width d2 of the collimator unit 2, which is the distance between the pair of plate-like portions (in other words, the X-ray introduction width in the vertical direction of the collimator unit 2), is larger than the thickness d1 of the X-ray detection element 35 (in other words, the width of the X-ray detection element 35 in the vertical direction). As a result, even if the above-mentioned angle deviation θ1 occurs, the X-rays 7 arrive at the entire area on the front surface of the collimator unit 2, making it possible to detect the X-rays 7, and thereby obtaining a desired resolution or detection sensitivity.

[0028] 8, the X-ray introduction width d2 of the collimator unit 2 is set to be equal to or greater than the sum of the thickness d1 of the X-ray detection element 35 and the error width d3 in the vertical direction based on the error angle of the movement control mechanism 11. This relationship can be expressed by the following equation (1).

[0029] d2 ≧ d1 + d3 × 2 (1)

[0030] In addition, the error width d3 is calculated based on the X-ray introduction length W, which is the length from the end of the collimator unit 2 on the X-ray source 5 side to the X-ray line sensor 3, and the angle deviation θ1, which is the error angle of the movement control mechanism 11, and can be expressed by the following equation (2).

[0031] d3=W×tanθ1 (2)

[0032] 9, when the X-ray introduction length W is, for example, 150 mm and the angular deviation θ1 is 0.5°, the error width d3 is calculated to be 1.31 mm from equation (2). Here, when the thickness d1 of the X-ray detection element 35 is, for example, 1 mm, the X-ray introduction width d2 is set to 3.62 mm or more from equation (1). In this case, it is preferable to set the X-ray introduction width d2 to, for example, 5 mm, further taking into consideration the accuracy of the angular deviation θ1, etc.

[0033] 10 , when the X-ray introduction length W is, for example, 200 mm and the angular deviation θ1 is 0.5°, the error width d3 is calculated to be 1.75 mm from equation (2). Here, when the thickness d1 of the X-ray detection element 35 is, for example, 2 mm, the X-ray introduction width d2 is set to 5.5 mm or more from equation (1). In this case, it is preferable to set the X-ray introduction width d2 to, for example, 7 mm, further taking into consideration the accuracy of the angular deviation θ1, etc.

[0034] Furthermore, in the X-ray detector 1, a shielding section 2S that blocks incidence of X-rays 7 is provided on the outer side in the vertical direction of the X-ray line sensor 3. X-rays 7 irradiated from the X-ray source 5 are diffusely reflected when passing through, for example, the subject 6, and the diffusely reflected X-rays (i.e., scattered rays) may be incident on the X-ray line sensor 3. In the conventional example of Fig. 7, when scattered rays are incident from outside the X-ray line sensor 3, as shown by the dashed arrows, the scattered rays arrive at the X-ray line sensor 3. Furthermore, when scattered rays are incident on the X-ray line sensor 3 after passing through part of the collimator section 2, as shown by the dash-dotted arrows, there is a risk that the collimator section 2 may not be able to prevent or completely prevent the scattered rays from being incident on the X-ray line sensor 3.

[0035] Therefore, in the X-ray detector 1, a shielding portion 2S is provided on the outer side of the X-ray line sensor 3 in the vertical direction to block the incidence of X-rays 7 from the outside. Specifically, as shown in FIG. 6 , the shielding portion 2S is provided so as to cover the entire vertical end faces of the X-ray line sensor 3. In other words, the shielding portion 2S is provided so as to shield the entire top and bottom faces of the X-ray line sensor 3 in the vertical direction. Note that, in order to prevent scattered rays from being incident on the X-ray line sensor 3, the shielding portion 2S is preferably provided so as to cover the entire vertical end faces of the X-ray line sensor 3, but may be provided so as to cover only a portion of them. In other words, as long as the shielding portion 2S is provided on the outer side of the X-ray line sensor 3 so as to cover at least a portion of the vertical end faces of the X-ray line sensor 3, it is possible to block the incidence of X-rays from the outside compared to a case in which the shielding portion 2S is not provided on the outer side of the X-ray line sensor 3. The width of the surface on which the shielding portion 2S is provided, that is, the length in the X direction, can be appropriately set depending on, for example, the amount of energy of the X-rays 7 and the predicted incident range (or incident direction) of scattered rays.

[0036] 6, the shielding portion 2S and the collimator portion 2 are integrally molded. That is, the collimator portion 2 and the shielding portion 2S are configured to be connected in the X direction using the same material (e.g., tungsten). In other words, compared to the conventional example of FIG. 7, the length of a pair of plate-like portions that function as the collimator portion 2 is extended in the X direction, and the plate-like portions and the X-ray line sensor 3 are configured to overlap when viewed from above and below.

[0037] 11 is a diagram showing an example comparing an X-ray transmission image of the X-ray detector 1 in the first embodiment with an X-ray transmission image of a conventional X-ray detector. (a) of FIG. 11 shows an example of an X-ray transmission image D11 captured by the X-ray detector 1 in the first embodiment, and (b) of FIG. 11 shows an example of an X-ray transmission image D12 captured by a conventional X-ray detector. Note that both X-ray transmission images D11 and D12 show a concrete member having reinforcing bars 6a as the subject 6. As can be seen from the X-ray transmission images D11 and D12, in the X-ray transmission image D12, shadows 6b appear in areas where X-rays 7 cannot be detected. In contrast, in the X-ray transmission image D11, there are no areas where X-rays 7 cannot be detected, making it a normal X-ray transmission image without shadows or the like.

[0038] As described above, in the first embodiment, the X-ray introduction width d2 of the collimator unit 2 is larger than the thickness d1 of the X-ray detection elements 35. Therefore, even if a slight deviation occurs in the angle of the X-ray detector in accordance with, for example, movement of the X-ray detector 1, the X-ray introduction width d2 is larger than the thickness d1 of the X-ray detection elements 35, and therefore it is possible to prevent the X-rays 7 from impinging on the tip portion or inner wall of the collimator unit 2. As a result, it is possible to prevent the occurrence of shadows and the like in the generated X-ray transmission image.

[0039] Furthermore, a shielding portion 2S that blocks the incidence of X-rays 7 is provided outside the X-ray line sensor 3 in the vertical direction. Therefore, even if scattered rays are incident from outside the X-ray line sensor 3, the scattered rays can be prevented from reaching the X-ray line sensor 3, and transmitted X-ray information from the subject can be accurately reflected in the generated X-ray transmission image. Consequently, a decrease in the image quality of the generated X-ray transmission image can be suppressed. In this way, by suppressing noise information due to scattered rays from being included in the generated X-ray transmission image, it is possible to suppress the X-ray transmission image from failing to achieve the desired resolution and detection sensitivity.

[0040] Furthermore, in the first embodiment, the shielding portion 2S is configured to cover the entire X-ray line sensor 3, including both end faces in the vertical direction. Therefore, the possibility of scattered rays reaching the X-ray line sensor 3 can be reduced compared to, for example, a case where the shielding portion 2S is provided to cover only a portion of the surface of the X-ray line sensor 3 in the vertical direction.

[0041] Furthermore, in the first embodiment, the shielding portion 2S and the collimator portion 2 are integrally molded. That is, a pair of plate-like portions that function as the collimator portion 2 extend to the outside of the X-ray line sensor 3 in the X direction. This makes it easier to manufacture the X-ray detector 1 and improves mechanical dimensional accuracy compared to, for example, a case in which the shielding portion 2S outside the X-ray line sensor 3 is formed from a separate member different from the collimator portion 2. Furthermore, if the shielding portion 2S is formed from a separate member, there is a possibility that a gap may be generated between the collimator portion 2 and the shielding portion 2S, causing problems such as scattered rays reaching the X-ray line sensor 3. However, by integrally molding the collimator portion 2 and the shielding portion 2S, the possibility of such problems occurring can be reduced.

[0042] Furthermore, in the first embodiment, as shown in the above-described formula (1), the X-ray introduction width d2 of the collimator unit 2 is set to be equal to or greater than the sum of the thickness d1 of the X-ray detection elements 35 and the error widths d3 in the vertical direction based on the error angle θ1 of the movement control mechanism 11. Therefore, when the X-ray introduction width d2 of the collimator unit 2 is set to be greater than the thickness d1 of the X-ray detection elements 35, the X-ray introduction width d2 takes a value according to the error angle θ1 of the movement control mechanism 11. Therefore, compared to when the X-ray introduction width d2 is set uniformly regardless of the error angle θ1, it is possible to prevent the X-ray detector 1 from becoming larger and to suppress the occurrence of shadows in the generated X-ray transmission images.

[0043] Next, other embodiments (second to seventh embodiments) will be described. In the following description, the same components as those in the first embodiment will be denoted by the same reference numerals, and the description thereof will be omitted or simplified.

[0044] Second Embodiment As described above, incident scattered rays on the X-ray line sensor 3 affect the generated X-ray transmission image. Therefore, it is preferable to prevent scattered rays from entering the X-ray line sensor 3 as much as possible. Therefore, in the second embodiment, in addition to the configuration of the first embodiment described above, a configuration for blocking X-rays is further provided. Specifically, as shown in FIG. 12 , the X-ray imaging system 100 has an opening 200 for introducing X-rays 7 and is provided with a housing 300 for blocking the incidence of X-rays 7 from outside. The X-ray detector 1 is housed in the housing 300 so that the X-rays 7 are introduced into the collimator unit 2 through the opening 200. In other words, the X-ray detector 1 is shielded by the housing 300 except for the opening 200, and detects X-rays 7 only from the opening 200. This makes it possible to prevent unnecessary scattered rays from entering the X-ray detector 1.

[0045] [Third Embodiment] When the X-ray detector 1 is used to inspect a bridge or other object 6, it is usually inspected outdoors, and changes in the outside air temperature may affect the measurement signal. As the temperature of the X-ray detector 1 increases, the dark current increases. When generating an X-ray transmission image, the measurement signal is calibrated using this dark current. However, if there is a difference between the dark current during imaging and the dark current during calibration, the image quality of the X-ray transmission image is affected. Therefore, it is necessary to correct the measurement signal during imaging for drift due to temperature during imaging. Therefore, in the third embodiment, the X-ray detector 1 is provided with a temperature sensor that measures the temperature of the X-ray detection element 35, and image information and temperature information are linked. The signal processing circuit 10 then corrects the X-ray transmission image based on the measured temperature (i.e., temperature information) measured by the temperature sensor, a predetermined reference temperature, and the measurement signal. This prevents degradation of the image quality of the X-ray transmission image due to the outside air temperature.

[0046] [Fourth Embodiment] In the above-described third embodiment, a temperature sensor is used to perform temperature correction of an X-ray transmission image. However, in a fourth embodiment, the X-ray source 5 is a pulsed X-ray source that irradiates X-ray pulses, such as a LINAC (an electron linear accelerator that generates X-rays with a maximum energy of 1 MeV or more), and the signal processing circuit 10 acquires non-irradiation signals between the X-ray pulses, and corrects the X-ray transmission image based on the non-irradiation signals.

[0047] That is, as shown in Fig. 13, the image signal for each line is corrected using a non-irradiation signal (dark output) during the period Toff when no X-ray pulse is irradiated. By using a pulsed X-ray source, it is possible to correct the image by obtaining a dark signal using the non-irradiation time of X-rays even during imaging, and therefore a more accurate X-ray transmission image can be obtained.

[0048] Fifth Embodiment As described above, when the temperature of the X-ray detector 1 rises due to changes in the outside air temperature, etc., the dark current increases. In particular, the higher the temperature of the X-ray detector 1, the greater the difference in dark current caused by temperature changes. For example, when the temperature of the X-ray detector 1 rises from 30°C to 31°C, the amount of change in dark current is greater than when the temperature of the X-ray detector 1 rises from 20°C to 21°C. Therefore, it is preferable to maintain the temperature of the X-ray detector 1 low. Therefore, in the fifth embodiment, as shown in FIG. 14 , a cooling mechanism 210 for cooling the interior of the housing 300 is provided in the housing 300 described in the second embodiment. This cools the interior of the housing 300, thereby preventing the temperature of the X-ray detector 1 from rising. The cooling mechanism 210 may be an air-cooled type using a fan or heat sink, a water-cooled type using a circulating refrigerant, or any other cooling method using a cooling element such as a Peltier element.

[0049] In addition to providing the cooling mechanism 210, the means for keeping the temperature of the X-ray detector 1 low may be configured such that the X-ray detector 1 and the signal processing circuit 10 are thermally isolated from each other within the housing 300. "Thermal isolation" means that the X-ray detector 1 and the signal processing circuit 10 are disposed at a distance from each other so that they do not thermally affect each other within the assumed temperature range of the X-ray detector 1 and the signal processing circuit 10, or that a heat shield is interposed between the X-ray detector 1 and the signal processing circuit 10. Thermal isolation can also be achieved by arranging the signal processing circuit outside the housing 300. If the X-ray detector 1 and the signal processing circuit 10 are not thermally isolated, the temperature of the X-ray detector 1 will rise due to heat generated by the electronic components 220, such as the circuit board, and the signal processing circuit 10. The X-ray detector 1 and the electronic components 220, and the electronic components 220 and the signal processing circuit 10, are electrically connected by wiring. By thermally isolating the X-ray detector 1 and the signal processing circuit 10 and placing them inside the housing 300 in this manner, it is possible to suppress the temperature rise of the X-ray detector 1 caused by the signal processing circuit 10.

[0050] Sixth Embodiment When the specimen 6 is made of thick concrete or the like, the amount of X-rays that penetrates the specimen 6 is small, and therefore the X-ray detector 1 is required to have high detection sensitivity. However, in order to achieve high detection sensitivity, the detection area of ​​the elements of the X-ray line sensor 3 must be increased. On the other hand, if the size of the detection area is increased, high resolution cannot be obtained. In other words, an X-ray line sensor having one type of detection area cannot simultaneously obtain high detection sensitivity and high resolution. On the other hand, when the thickness of the specimen 6 changes or depending on the inspection content of the specimen 6, there are cases where high detection sensitivity or high resolution is desired to be prioritized.

[0051] FIG. 15 is a diagram illustrating the configuration of an X-ray detector 40 according to a sixth embodiment. As shown in FIG. 15 , the X-ray detector 40 includes an X-ray line sensor 41 having a first X-ray detection element row and an X-ray line sensor 42 having a second X-ray detection element row, arranged vertically. The detection area S1 of the elements in the first X-ray detection element row of the X-ray line sensor 41 is different from the detection area S2 of the elements in the second X-ray detection element row of the X-ray line sensor 42, with the detection area S2 being larger than the detection area S1. Note that in the example of FIG. 15 , the first X-ray detection element row and the second X-ray detection element row are depicted with different horizontal (±Y) pitches (i.e., the horizontal pitch of the second X-ray detection element row is depicted as being larger than the horizontal pitch of the first X-ray detection element row), but the method for differentiating the detection areas is not limited thereto. For example, the detection areas may be different by aligning the horizontal pitch and varying the vertical (±Z) lengths. Although the configuration of the collimator unit 2 is omitted, the configuration of the collimator unit 2 may be arranged in the same positional relationship as in the above-described embodiment. That is, the collimator unit 2 is arranged so as to sandwich the group of X-ray line sensors, regarding the X-ray line sensors 41 and 42 as one (group of) X-ray line sensors, and is closer to the X-ray source 5 than the end of the group of X-ray line sensors.

[0052] In this case, an X-ray transmission image D21 is obtained from the X-ray line sensor 41, and an X-ray transmission image D22 is obtained from the X-ray line sensor 42. The X-ray transmission image D21 has a higher resolution than the X-ray transmission image D22, and the X-ray transmission image D22 has a higher detection sensitivity than the X-ray transmission image D21.

[0053] In this way, in the sixth embodiment, a high-resolution X-ray transmission image D21 and a high-detection-sensitivity X-ray transmission image D22 can be simultaneously obtained by a single scan. Note that the number of rows of X-ray detection elements arranged in a vertical line is not limited to two, and three or more rows of X-ray detection elements may be arranged.

[0054] Furthermore, even if the detection areas S1 and S2 are the same, the detection sensitivity can be increased by combining the measurement signals of the X-ray line sensors 41 and 42 as necessary.

[0055] Seventh Embodiment FIG. 16 is a diagram illustrating the configuration of an X-ray detector 50 according to a seventh embodiment. In the example shown in FIG. 16 , similar to the sixth embodiment, an X-ray line sensor 51 having a first X-ray detection element array and an X-ray line sensor 52 having a second X-ray detection element array are arranged vertically side by side. In the seventh embodiment, the detection areas of the X-ray detection elements in each of the X-ray line sensors 51 and 52 are the same detection area S1. However, the X-ray detection element arrays of the X-ray line sensor 51 and the X-ray line sensor 52 are arranged offset horizontally. Although the collimator unit 2 is omitted in the example of FIG. 16 , the collimator unit 2 may be arranged in the same positional relationship as in the above-described embodiments. That is, the X-ray line sensors 51 and 52 are collectively regarded as a single (group of) X-ray line sensors, and the collimator unit 2 is arranged to sandwich the group of X-ray line sensors and closer to the X-ray source 5 than the end of the group of X-ray line sensors.

[0056] In this way, when a single X-ray line sensor is constructed by arranging multiple X-ray detection element rows horizontally, gaps tend to form at the joints between the X-ray detection element rows, but the loss of information caused by these gaps can be compensated for by one of the X-ray detection element rows that is arranged offset in the horizontal direction, thereby enabling the acquisition of a higher-resolution X-ray transmission image.

[0057] [Others] While the above describes each embodiment with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0058] For example, the X-ray line sensor 3 in each of the above-described embodiments is composed of an X-ray detection element 35 that combines a scintillator 31 and a photodetector 32, but is not limited to this and may be a semiconductor line sensor that directly detects X-rays.

[0059] Furthermore, in the above-described embodiment, the collimator unit 2 is configured to sandwich the X-ray line sensor 3 in the vertical direction when viewed from the X-ray source 5 side, but it may also be configured to sandwich the X-ray line sensor 3 from the left and right directions in addition to the vertical direction when viewed from the X-ray source 5 side. That is, when viewed from the X-ray source 5 side, the collimator unit 2 may surround the X-ray line sensor 3 in the vertical and horizontal directions except for the direction of irradiation of the X-rays 7. Alternatively, it may be configured in at least one of the horizontal and vertical directions in addition to the vertical direction. This makes it possible to further prevent scattered rays from entering the X-ray line sensor 3.

[0060] Furthermore, for example, in the first embodiment, the shielding portion 2S and the collimator portion 2 are configured to be integrally molded, but the shielding portion provided on the outside of the X-ray line sensor 3 does not need to be integrally molded with the collimator portion 2 as long as it is configured to block scattered rays. In other words, the shielding portion 2S may be made of a material different from the collimator portion 2. Possible materials for making such a shielding portion include, for example, molybdenum, lead, etc.

[0061] 17 to 19 as long as the positional relationship between the shielding unit 2S and the collimator unit 2, which are made of different members, is capable of blocking scattered rays from entering the X-ray line sensor 3. The example shown in Fig. 17 shows an example in which a gap is provided between the shielding unit 2S and the collimator unit 2. That is, in the above-described embodiment, the shielding unit 2S and the collimator unit 2 are configured to be continuous in the X direction, but in the example shown in Fig. 17, a gap is provided between the shielding unit 2S and the collimator unit 2 in the X direction.

[0062] 18, the shielding section 2S may be arranged inward from the collimator section 2 in the vertical direction (Y direction), and the width in the vertical direction may be smaller than the width of the collimator section 2. Furthermore, as shown in FIG. 19, the shielding section 2S may be arranged outward from the collimator section 2 in the vertical direction (Y direction), and the width in the vertical direction may be larger than the width of the collimator section 2.

[0063] This specification describes at least the following items. Note that the components in parentheses correspond to those in the above-described embodiment, but are not limited to these.

[0064] (1) An X-ray imaging system (X-ray imaging system 100) comprising: an X-ray source (X-ray source 5) that irradiates X-rays (X-rays 7); an X-ray detector (X-ray detector 1, 40, 50) that is arranged to face the X-ray source across an object (object 6) and detects the X-rays that have passed through the object; and a movement control mechanism (movement control mechanism 11) that moves the X-ray detector in a predetermined direction (up and down direction), wherein the X-ray detector comprises: an X-ray line sensor (X-ray line sensor 3) that is linearly arranged along a direction (horizontal direction) that intersects with the predetermined direction so that a plurality of X-ray detection elements (X-ray detection elements 35) face the X-ray source; and a pair of plate-like parts that are arranged opposite to each other in the predetermined direction, that are arranged on either side of the X-ray line sensor when viewed from the X-ray source side and are closer to the X-ray source than the end of the X-ray line sensor, and that introduces the X-rays into the X-ray detection elements. the movement control mechanism has a mechanism (first drive unit 11a, second drive unit 11b) that moves the X-ray detector and causes the introduction direction of the X-rays in the collimator unit to face the X-ray source; the X-ray introduction width (X-ray introduction width d2) of the collimator unit, which is the distance between the pair of plate-like portions, is larger than the thickness of the X-ray detection element (thickness d1 of the X-ray detection element); and a shielding portion (shielding portion 2S) that blocks the incidence of the X-rays is provided outside the X-ray line sensor in the predetermined direction. X-ray imaging system.

[0065] According to (1), even if a slight deviation occurs in the angle of the X-ray detector, the X-ray introduction width of the collimator unit is larger than the thickness of the X-ray detection element, so that it is possible to prevent X-rays from hitting the tip portion or inner wall of the collimator unit, and as a result, it is possible to prevent the occurrence of shadows, etc. in the generated X-ray transmission image. In addition, since a shielding unit is provided on the outside in a predetermined direction of the X-ray line sensor, it is possible to prevent scattered rays from reaching the X-ray line sensor, and it is possible to prevent the occurrence of shadows, etc. in the generated X-ray transmission image.

[0066] (2) The X-ray imaging system according to (1), wherein the shielding portion entirely covers both end faces of the X-ray line sensor in the predetermined direction.

[0067] According to (2), since the shielding portion is arranged to cover the entire end faces of the X-ray line sensor in a predetermined direction, the possibility of scattered rays reaching the X-ray line sensor can be reduced compared to, for example, a case where the shielding portion is arranged to cover only a portion of the X-ray line sensor in a predetermined direction.

[0068] (3) The X-ray imaging system according to (1) or (2), wherein the shielding section and the collimator section are integrally molded.

[0069] According to (3), in the manufacturing process of the X-ray detector 1, the manufacturing of the X-ray detector becomes easier compared to when the collimator portion and the shielding portion are not integrated or are not made of the same material.

[0070] (4) The X-ray imaging system according to (1) or (2), further comprising a housing (housing 300) having an opening (opening 200) for introducing the X-rays and blocking the incidence of the X-rays from outside, wherein the X-ray detector is housed in the housing so that the X-rays are introduced into the collimator section through the opening.

[0071] According to (4), unnecessary scattered rays can be prevented from being incident on the X-ray detector.

[0072] (5) The X-ray imaging system according to (4), wherein the housing is provided with a cooling mechanism (cooling mechanism 210) that cools the inside of the housing.

[0073] According to (5), the inside of the housing is cooled, and the temperature of the X-ray detector can be prevented from rising.

[0074] (6) The X-ray imaging system according to (4), further comprising a signal processing circuit (signal processing circuit 10) that processes a measurement signal measured by the X-ray detector to generate an image, and the X-ray detector and the signal processing circuit are arranged inside the housing so as to be thermally separated.

[0075] According to (6), it is possible to suppress a temperature rise in the X-ray detector caused by the signal processing circuit.

[0076] (7) An X-ray imaging system according to (1) or (2), wherein the X-ray detector (X-ray detectors 40, 50) includes a first X-ray detection element row (X-ray line sensor 41, X-ray line sensor 51) in which the plurality of X-ray detection elements are arranged linearly in a line along a direction intersecting with the predetermined direction, and a second X-ray detection element row (X-ray line sensor 42, X-ray line sensor 52) in which the plurality of X-ray detection elements are arranged linearly in a line along a direction intersecting with the predetermined direction, and the first X-ray detection element row and the second X-ray detection element row are arranged side by side in the predetermined direction.

[0077] According to (7), when the object is thick concrete or the like, even if the amount of X-rays passing through the object is small, by providing multiple rows of X-ray detection elements above and below, high detection sensitivity can be obtained in the X-ray detector.

[0078] (8) The X-ray imaging system according to (7), wherein the elements of the first X-ray detection element row (X-ray line sensor 41) and the elements of the second X-ray detection element row (X-ray line sensor 42) have different X-ray detection areas (S1, S2).

[0079] According to (8), by using X-ray detection elements with different detection areas, high detection sensitivity and high resolution can be obtained at the same time.

[0080] (9) The X-ray imaging system according to (7), wherein the elements of the first X-ray detection element row (X-ray line sensor 51) and the elements of the second X-ray detection element row (X-ray line sensor 52) have the same detection area of ​​the X-rays and are arranged to be shifted in a direction intersecting the predetermined direction.

[0081] According to (9), when a single X-ray line sensor is constructed by arranging a plurality of X-ray detection element rows in the horizontal direction, gaps tend to occur due to the joints between the X-ray detection element rows, but the loss of information caused by these gaps can be compensated for by one of the X-ray detection element rows arranged offset in the horizontal direction, thereby making it possible to obtain a higher-resolution, high-quality X-ray transmission image.

[0082] (10) An X-ray imaging system according to (1) or (2), wherein the X-ray introduction width of the collimator section is equal to or greater than the sum of the thickness of the X-ray detection element, an X-ray introduction length (X-ray introduction length W) which is the length from the end of the collimator section on the X-ray source side to the X-ray line sensor, and twice the value of the error width (error width d3) in the specified direction calculated based on the error angle (angular deviation θ1) of the movement control mechanism.

[0083] According to (10), when the size of the X-ray introduction width of the collimator section is made larger than the thickness of the X-ray detection element, the X-ray introduction width is set to a value corresponding to the error angle of the movement control mechanism. Therefore, compared to when the X-ray introduction width is set uniformly regardless of the error angle, it is possible to suppress the occurrence of shadows in the generated X-ray transmission image while avoiding an increase in the size of the X-ray detector.

[0084] (11) The X-ray imaging system according to (1) or (2), wherein the X-ray detection element has a scintillator (scintillator 31) and a photodetector (photodetector 32) that detects scintillation light emitted by the scintillator.

[0085] According to (11), X-rays are converted into light by a scintillator, which is an X-ray detection element, and the converted light can be detected by a photodetector.

[0086] (12) The X-ray imaging system according to (6), further comprising a temperature sensor that measures the temperature of the X-ray detection element, and the signal processing circuit corrects the X-ray transmission image based on the measured temperature measured by the temperature sensor and information on the relationship between a reference temperature and the measurement signal.

[0087] According to (12), by correcting the X-ray transmission image, it is possible to prevent the image quality of the X-ray transmission image from being deteriorated due to the outside air temperature or the like.

[0088] (13) The X-ray imaging system according to (6), wherein the X-ray source is a pulsed X-ray source that irradiates X-ray pulses, and the signal processing circuit acquires a non-irradiation signal between the X-ray pulses and corrects the X-ray transmission image based on the non-irradiation signal.

[0089] According to (13), even during imaging, it is possible to correct the image by acquiring a dark signal using the non-irradiation time of X-rays, so that a more accurate X-ray transmission image can be obtained.

[0090] In the above-described embodiment, if the shielding portion 2S and the collimator portion 2 are integrally molded and referred to as an X-ray functional member, the following matters will be described in this specification.

[0091] (14) An X-ray imaging system (X-ray imaging system 100) including: an X-ray source (X-ray source 5) that irradiates X-rays (X-rays 7); an X-ray detector (X-ray detector 1, 40, 50) that is arranged to face the X-ray source across a subject (subject 6) and detects the X-rays that have passed through the subject; and a movement control mechanism (movement control mechanism 11) that moves the X-ray detector in a predetermined direction (up and down direction), wherein the X-ray detector includes: an X-ray line sensor (X-ray line sensor 3) that is linearly arranged along a direction (horizontal direction) that intersects with the predetermined direction so that a plurality of X-ray detection elements (X-ray detection elements 35) face the X-ray source; and an X-ray functional member (collimator unit 2+shielding unit 2S) that is a pair of plate-like parts that are arranged opposite to each other in the predetermined direction, and that are arranged to sandwich the X-ray line sensor when viewed from the X-ray source side and to extend toward the X-ray source from a region including an end of the X-ray line sensor. the movement control mechanism has a mechanism (first drive unit 11a, second drive unit 11b) that moves the X-ray detector and causes the introduction direction of the X-rays in the X-ray functional member to face the X-ray source, an X-ray introduction width (X-ray introduction width d2) of the X-ray functional member that is the distance between the pair of plate-shaped portions is larger than a thickness of the X-ray detection element (thickness d1 of the X-ray detection element), and the X-ray functional member is arranged to overlap with the X-ray line sensor when viewed from the predetermined direction.

[0092] In addition, the X-ray functional member has the function of introducing X-rays into the X-ray detection element (collimation function) in the area closer to the X-ray source than the end of the X-ray line sensor, and has the function of preventing scattered rays from entering the X-ray line sensor (shielding function) in the area overlapping with the X-ray line sensor.

[0093] According to (14), even if a slight deviation occurs in the angle of the X-ray detector, the X-ray introduction width of the X-ray functional member is larger than the thickness of the X-ray detection element, so that X-rays can be prevented from hitting the tip portion or inner wall of the X-ray functional member, and as a result, the occurrence of shadows, etc. in the generated X-ray transmission image can be prevented. In addition, the X-ray functional member is provided on the outside in a predetermined direction of the X-ray line sensor, so that scattered rays can be prevented from reaching the X-ray line sensor, and the occurrence of shadows, etc. in the generated X-ray transmission image can be prevented.

[0094] This application is based on a Japanese patent application (Patent Application No. 2024-055561) filed on March 29, 2024, the contents of which are incorporated herein by reference.

[0095] 1, 40, 50 X-ray detector 2 Collimator section 2S Shielding section 3 X-ray line sensor 5 X-ray source 6 Subject 7 X-ray 10 Signal processing circuit 11 Movement control mechanism 11a First driving section 11b Second driving section 31 Scintillator 32 Photodetector 35 X-ray detection element 41, 51 X-ray line sensor (first X-ray detection element row) 42, 52 X-ray line sensor (second X-ray detection element row) 100 X-ray imaging system 200 Opening (aperture) 210 Cooling mechanism 300 Housing d2 X-ray introduction width d3 Error width S1, S2 Detection area W X-ray introduction length θ1 Angle deviation (error angle)

Claims

1. An X-ray imaging system comprising: an X-ray source that irradiates X-rays; an X-ray detector that is arranged to face the X-ray source across an object and detects the X-rays that have passed through the object; and a movement control mechanism that moves the X-ray detector in a predetermined direction, wherein the X-ray detector has: an X-ray line sensor that is arranged linearly along a direction intersecting the predetermined direction so that a plurality of X-ray detection elements face the X-ray source; and a collimator unit that is a pair of plate-like parts that are arranged opposite to the predetermined direction, sandwiching the X-ray line sensor when viewed from the X-ray source side and that is arranged closer to the X-ray source than an end of the X-ray line sensor, and that introduces the X-rays into the X-ray detection elements, and the movement control mechanism has a mechanism that moves the X-ray detector so that the introduction direction of the X-rays in the collimator unit faces the X-ray source, and the X-ray introduction width of the collimator unit, which is the distance between the pair of plate-like parts, is greater than the thickness of the X-ray detection elements, an X-ray imaging system, wherein a shielding portion that blocks incidence of the X-rays is provided on an outer side of the X-ray line sensor in the predetermined direction.

2. An X-ray imaging system according to claim 1, wherein the shielding portion entirely covers both end faces of the X-ray line sensor in the predetermined direction.

3. An X-ray imaging system according to claim 1 or 2, wherein the shielding section and the collimator section are integrally molded.

4. An X-ray imaging system according to claim 1 or 2, comprising a housing having an opening for introducing the X-rays and blocking the incidence of the X-rays from outside, and the X-ray detector is housed in the housing so that the X-rays are introduced into the collimator section through the opening.

5. An X-ray imaging system according to claim 4, wherein the housing is provided with a cooling mechanism for cooling the inside of the housing.

6. An X-ray imaging system according to claim 4, further comprising a signal processing circuit that processes measurement signals measured by the X-ray detector to generate an image, and the X-ray detector and the signal processing circuit are arranged inside the housing so as to be thermally isolated.

7. An X-ray imaging system according to claim 1 or 2, wherein the X-ray detector comprises: a first X-ray detection element row in which the plurality of X-ray detection elements are arranged in a linear row along a direction intersecting with the predetermined direction; and a second X-ray detection element row in which the plurality of X-ray detection elements are arranged in a linear row along a direction intersecting with the predetermined direction, and the first X-ray detection element row and the second X-ray detection element row are arranged side by side in the predetermined direction.

8. An X-ray imaging system according to claim 7, wherein the elements of said first X-ray detection element row and the elements of said second X-ray detection element row have different X-ray detection areas.

9. An X-ray imaging system according to claim 7, wherein the elements of the first X-ray detection element row and the elements of the second X-ray detection element row have the same X-ray detection area and are arranged with a shift in a direction intersecting the predetermined direction.

10. An X-ray imaging system according to claim 1 or 2, wherein the X-ray introduction width of the collimator section is equal to or greater than the sum of the thickness of the X-ray detection element, the X-ray introduction length which is the length from the end of the collimator section on the X-ray source side to the X-ray line sensor, and twice the value of the error width in the specified direction calculated based on the error angle of the movement control mechanism.

11. An X-ray imaging system according to claim 1 or 2, wherein the X-ray detection element comprises a scintillator and a photodetector that detects scintillation light emitted by the scintillator.

12. An X-ray imaging system according to claim 6, further comprising a temperature sensor for measuring the temperature of the X-ray detection element, and wherein the signal processing circuit corrects the X-ray transmission image based on the temperature measured by the temperature sensor and information relating to the relationship between a reference temperature and the measurement signal.

13. An X-ray imaging system according to claim 6, wherein the X-ray source is a pulsed X-ray source that irradiates X-ray pulses, and the signal processing circuit acquires non-irradiation signals between the X-ray pulses and corrects the X-ray transmission image based on the non-irradiation signals.

Images